Laser detection system and method for concentration of harmful gas in atmosphere of open space

Abstract

The invention discloses a laser detection system and method for concentration of harmful gas in an atmosphere of an open space. The laser detection system comprises a same-frequency dual-wave laser signal generation unit, a signal acquisition and processing unit, a display unit, a detection optical path and a reference optical path. By virtue of the steps of correcting the movement of center wavelength of a distribution feedback-type semiconductor laser, correcting flash noise, fitting complete non-absorptive spectral signal, normalizing, performing Voigt linear fitting, calculating the concentration, performing the inversion, and the like, the problems such as atmospheric extinction, laser flashing and wavelength drifting can be prevented, so that the real-time precision detection of thegas concentration can be realized.

Description

Technical field [0001] The invention relates to the field of environmental optics, in particular to a system and method for suppressing atmospheric turbulence noise by means of multi-wavelength time-domain correlation technology, and detecting gas concentration by laser spectrum. Background technique [0002] In the process of monitoring the open space atmosphere, the concentration of the detected gas is relatively low, but it is affected by the uncontrollable environment such as atmospheric turbulence and temperature, which causes the problem that useful signals and noise are difficult to extract. Atmospheric turbulence mainly causes the laser's scintillation effect caused by the change of the refractive index of the atmospheric molecular clusters to cause the beam to produce intensity fluctuations, phase fluctuations, beam expansion, beam drift, and image point jitter, resulting in linear deformation of the gas absorption spectrum. [0003] The existing reduction in the influence...

AI Technical Summary

Problems solved by technology

However, in the actual application of the development of the instrument system, the influence of atmospheric turbulence is more complicated, which may easily cause detection errors

To reduce the influence of atmospheric turbulence through a high scanning frequency, the bandwidth of the laser control module is limited, so the high-frequency scanning method is limited in the development of the instrument system; increasing the receiving aperture reduces the loss of light intensity in a certain sense, but It does not fundamentally address the influence of atmospheric turbulence on spectral signals

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